1. Field of the Invention
The present invention relates to a spoiler in which an outer member and an inner member that are made of a synthetic resin are welded and fixed and then are integrated with each other.
2. Description of the Related Art
A variety of spoilers are employed for the purpose of improvement in steering property or in travelling stability of an automobile. For example, a front spoiler has an advantageous effect of restraining inflow of air to a lower face of a vehicle body to thereby restrain an occurrence of a lifting force, and a side spoiler effectively has an advantageous effect of feeding the air flowing to both sides of the vehicle to thereby restrain an occurrence of an eddy on the rear side of the vehicle body.
These spoilers each are generally composed of an outer member and an inner member that are made of a synthetic resin, and the outer member and the inner member are integrated with each other by a variety of means. The outer member is a member that serves as an external view of a spoiler in the case where the spoiler is mounted on the vehicle body, and the inner member is a member that is positioned at an interior face side of the outer member, and that is used to be mounted on the vehicle body.
A vibration welding method is known as one of methods for integrating an outer member and an inner member with each other (for example, Japanese Unexamined Patent Application Publication No. 2012-061897). The vibration welding method is a method for arranging and pressurizing an outer member and an inner member in their coupled state and then vibrating and thermally welding one of these two members in a direction vertical to a pressurization direction. In order to thermally weld both of the members, a weld rib is formed at a part at which the outer member and the inner member come into contact with each other. As described previously, in a state in which the weld rib is welded due to a heat of the pressurization and vibration, the rib is fixed at its predetermined position and then the rib is cooled to thereby cause the outer member and the inner member to be integrated with each other in their coupled state.
While the weld rib is welded due to a frictional heat with a contact part of the outer member or the inner member, in the case where a weld rib is formed on a face inclined with respect to the pressurization direction, a contact area becomes larger than a vertical face. Thus, in the case of a conventional substantially hemispherical weld rib as shown in FIG. 7, there has been a problem that a timing at which the weld rib starts welding is likely to shift depending on a location. Further, if part of the weld rib starts welding, a contact area with a counterpart member suddenly increases and therefore there has been a problem that a stable welding quality of the whole product is hardly assured.
In view of the problem described above, the present invention aims to provide a spoiler in which even in the case where a weld face is inclined with respect to a pressurization direction, a weld rib is uniformly welded and then an outer member and an inner member are welded and fixed to each other at a stable strength, the spoiler having an excellent welding quality of its whole product.